Figure 3.

Toxicity in cells upon induction of wild-type or G57C mutant tisB mRNA. (A) E. coli cells carrying the plasmids pBAD control (ct; empty vector control), pBAD +42, or pBAD +42 G57C, were grown to mid-exponential phase (OD₆₀₀ = 0.5) before addition of 0.2% glucose. Time of glucose addition is indicated by a red arrow. (B) Same protocol as in (A), but with induction of mRNA transcription by 0.2% arabinose. (C) Ten-fold serial dilutions of bacterial cultures 30 min post-induction by either glucose (left) or arabinose (right) were spotted on LA-amp plates. As indicated, spotting assays were also done with plasmids encoding delayed-active +1 tisB mRNA (see Results).